1. Field of the Invention
This invention relates to an apparatus for examining tubular members disposed in axially parallel relationship with each other.
2. Description of the Prior Art
Generally, there are several spots in a nuclear/thermal power plant and the chemical plant, each including a number of tubular members disposed in axially parallel relationship with each oher at narrow intervals. For example, as shown in FIG. 6, a number of adapters 02 for mounting respective control rod drive units are provided in the upper section of a cap 01 of a pressurized water reactor, to the respective upper portions of these mounting adaptors 02 being welded individual control rod drive units 03 (only one being illustrated), so that they are disposed in axially parallel relationship or stand close together. Reference numeral 04 designates a drive shaft shroud tube.
In connection with such a structure, it is natural to examine the welded portions of the mounting adapters 02 and control rod drive units 03, however, because these control rod drive units 03 are disposed at narrow intervals it is impossible to position an ultrasonic flaw detector and the like at a predetermined position. Hence, in the prior art, these welded portions were inspected, for example, through visual examination using a mirror, or by pressurizing the inside of each tube and checking external leakage.
However, because the spot being subjected to examination is narrow, either of the aforementioned procedures is carried out only with considerable difficulty and it is hard to say that a trustworthy and sufficient examination can be performed. Further, there is the inconvenience that the working hours are limited because the work is performed in a radioactive atmosphere.